Furnace



(No Model.) 4 Sheets-Sheet l.

. J.. K. THOMPSON;

' EURNAGB.

. No. 505,143, Patenteds ept.19,139s.

(No Model.) 4 Sheets-Sheet 2.

J. KQ THOMPSON. PURNACE. i

10.505,143. Patented sep-t.-19,`189s.

.. 0 s* P AMV 0. H m,... K TUI (No Model.)

FURNAGB.

Patented Sept. 19, 18:93.

UNITED STATES PATENT OEEIcE.

JAMES KNAPTON THOMPSON, OF LEEDS, ENGLAND, ASSIGNOR OF TWO- THIRDS TO CHARLES F. JAHN, OF PITTSBURG, PENNSYLVANIA.

FURNACE.

SPECIFICATION forming part of Letters Patent No. 505,143, dated September 19, 1893.

Application filed May 2,1893. Serial No. 472,654. (No model.) Patented in England January 28, 1891, No. 1,565.

To all whom it may concern:

Be it known that I, J AMES KNAPTON THOMP- SON, a subject of the Queen of Great Britain, residing at Leeds, county of York, England, have invented certain new and useful Improvements in Furnaces, (for a portion of which I have obtained a patent in Great Britain, dated January 28, 1891, No. 1,5655) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it apperfains to make and use the same.

This invention relates more especially to fire-boxes or hearths of' furnaces for steamboilers, although the same maybe applied to other heating apparatus of all kinds, such as ovens or kilns of every description and flues connected therewith, for economizing coal and other fuel and preventing smoke.

The object of the said invention is to economize coal and other fuel and to prevent the generation of smoke, by securing perfect combustion of fuel, and for this purpose my invention consists in the features, devices and combinations of parts as hereinafter described and pointed out in theclaims, whereby the hydro -carbon and other gases and vapors evolved'from the fuel during combustion are first saturated and intimately mixed with the necessary volume of oxygen and the resulting mixture of gases arerthen led or carried down to the bottom of the hre-box through the entire mass of incandescent fuel therein,

whereby the mixed gases are quickly brought to the proper temperature to ignite and produce pure Hanne, the resulting carbonio acid gas and other products of combustion passing away and perfect combustion being effected and the whole of the fuel being properly burnedV and the maximum amount of heat or caloric obtained therefrom.

In the drawings which represent some of the various ways of carrying out my invention-Figure 1 represents a longitudinal vertical section of so much of a steam-boiler furnace as necessary to illustrate the invention; Fig. 2 a sectional plan on line 2-2, Fig. l; Fig. 3 a detail view slightly modified. Fig. 4, is a detail view of the fuel feeding rollers; Fig. 5 a longitudinal vertical section of a modified form of furnace; Figs. 6, 7, 8 and 9 sectional views of other modified forms of furnace, to be explained hereinafter; Figs. 10 and l1 detail views; Figs. 12 and 13 vertical longitudinal sections of two further modifications.

Referring first to Figs. l to 4, inclusive, it

will be seen thatin the preferred form of the boiler furnace embodying my invention, the lire-box, A, is constructed with the sides all inclined away from a vertical line and from each other at a suitable angle, so as to form an inverted conical or pyramidal space, the narrow part being at the top so as to facilitate thefree movement and falling down of the fuel from the top to the base of the firebox and prevent the clogging of fuel and adhesion of clinkers, as well as topreserve a constant bed of incandescent fuel or fire at the bottom of the fire-box.

Arranged inside and forming the back of this fire-box is a depending partition or inverted bridge, B, Fig. 1, which (with the two ends, when so required), extends downward in an unbroken line to within a short distance of the bottom grate and without having any openings or lines into or through which any portion of the mixture of combustible gases may escape before ignition and leaving only sufficient space between the said grate and the lower edge of the said inverted bridge for the passage, into vthe main iiue and flame chamber, O, of the heat and flame produced by the said mixture of combustible gases, which, it is most essential and necessary', shall first pass through the entire mass of incandescent fuel at the front side of the said bridge in the fire-box, so that the whole of such gases shall be thoroughly consumed and the escape of any portion thereof in an unconsumed state into any flue before reaching the bottom of the said inverted bridge is there.

by prevented or rendered impossible, while said bridge always retains the solid fuel and incandescent re' withinA the fire-box so that none of it can enter the lines. This bridge may be made solid or preferably, as in the present case, Where it is connected with a boiler furnace, it is made hollow to form a water-back communicating with the boiler, D.

The front wall, E, of the fire-boxis provided saV IOO

With openings or slots along substantially its entire extent to permit the access of a sufficient supply of air to the entire column or mass of fuel in the fire-box. In the present instance, this front wall is formed by placing horizontal bars, E', of suitable triangular, or approximately triangular, shape across the front side of the fire-place at suitable distances from, and preferably overlapping, each other, as shown in Figs. l and 3. This arrangement of the bars enhances the downdraft and at the same time, facilitates the descent of the fuel, as will be readily understood. On the outside of these bars, I provide sliding slotted shutters, E2, Figs. l and 3, having their bars so arranged that thev whole of the re may be completely closed in, or they may be left partly open to regulate the supply of air and to facilitate firing Q up for long periods of absence. For this purpose, the shutters may be almost closed and the dampers correspondingly shut so that the volume of air passing through the fuel may be so regulated as to be sufficient to keep the fire alive and burning all night with a minimuml consumption of fuel, thereby rendering relighting in the morning unnecessary and, the fire being practically closed in, obviating the damage from sparks or flying coals. door, e, which may be of any suitable form, is

provided at the bottom of the'tire-box, to allow the removal of ashes, clinkers, dto'. In front of the bridge', B, I also p-referably provide an additional arrangement consisting of a plate or bar, ct whichdoes not reach to the top of the lire-box and extends downwardly only sufficiently to allow the bottom edge to touch the incandescent fuel. This plate, which I term the pilot-plate, is fixed in the firebox parallel with the bridge and distant from it about oneinch ormore,leavinga small spaceorchannel through which the gases generated by an excessive feed-of fuel, can readily escape over the top' of said plate and pass down the said 'channel until they enter theincandescent fuel and mingle with the other combustiblegases as indicated by the arrows. This pilot-plate may sometimes be arranged on another wall of the fire-box,l such as one of the side walls, as indicatedin Fig. 9. I also provide means for furnishing a constant supply of water below the bottom grate preferably located in the ash pit, G, as shown in Fig. l. This ash pit consists ofa tray made to lit closely against the furnace, so as to prevent the access of air. In this tray is arranged a means for constantly supplying Water, or thetray may be partially filled with water, as shown, which, by evaporation, rises in th'e form of aqueous vapor and passes into the incandescent fuel or into the highly heated gas-es, and is there decomposed. The hydrogen is thus set free and quickly combines with the hydro-carbon and other combustible gases along with the oxygen, alsoliberated from the water, thereby producing ahighly inflammable mixture of gases, which, on becoming ignited, assists in the perfect combustion of the fuel, thus creating intense heat. Another very valuable function of the aqueous vapor is to keep the bottom grate cool and thus prevent .its destruction by the intense heat of the incandescent fuel resting upon the same. The caloric of the grate bars, thus abstracted, is returned to the hearth, where it is made available for the heating of the boiler and does not become wasted.

It will be observed from the above that my furnace consists essentially in abottom-grate, preferably horizontal, a front wall provided with a series of air-openings extending to the grate, a continuous, unbroken lire-back extending down within a short distance of the grate, so as to retain all the fuel in the firebox and an ash-pit or space arranged below i the grate provided with means for entirely excluding the access of air to the grate from below. I have found, by a long series of experiments andk researches extending over 1 many years, that this is the only arrangement which insures the complete combustion of the fuel, this result being due to the fact that all of the air of combustion and all of v the hydrocarbons and other gasesevo'lved are forced through the lowerrnost stratum of highly incandescent fuel, whereby they are not onlyT thoroughly intermingled and exposed to that degree of heat necessary to their complete combustion,- but the free oxygen of the air of combustion is combined with the incandescent coal in such a' manner as to completely consume the same and hence prevent the formation of smoke, or carbonicoxideinstead of carbonio acid, from that source. There is, moreover, a very important advantage derived, from providing the front wall of the lirefbox With a series of openings extending down to the grate, by virtue of the fact that, under this construction, fresh air is permitted to intermingle with the gases evolved in the various strata of the fuel in the fire-box and thus more effectually insures the perfect combustion of these gases, than in those constructions where the air of com.-

bustion is fed to the top of the fuel only, and

hence has to passthrough all the upper strata of the same before it reaches the gases in the lower strata. A supply of gas from the top is, moreover, objectionable for the reason that the gases evolved in the body of the fuel have a tendency to create a back-pressure which results in preventing the necessary amount of oxygen from passing through the fuel in a given period of time. The openngsin the front Wall, in connection with the continuous, unbroken fire-bridge and the hermetically closed space below the grate, enable me to obtain a down-draft through the fuel, and, at the same time, to avoid the evil consequences which attended the former devices for effecting such down-draft.

It is highlyimportant that the bottom-grate be horizontal because otherwise the fuel will have a tendency to pass over into the combustion-chamber, C, and to clog up the nar- IOO IIO

row passage way between the grate,.F, and the fire-bridge, B, whereas it is essential-to the smokeless and complete combustion of the fuel that the same will all remain within the fire-box, and the opening into the combustion-chamber will remain free. Only under such an arrangement is it possible to maintain the necessary down-draft and consequent adequate supply of oxygen to the fuel and to prevent the escape of unconsumed gases which would be generated if the fuel would pass over into the flame-chamber, C.

I do not herein claim the method of, and means set forth for, producing these aqueous vapors, inasmuch as the same forms the subject-matter of an application filed by me June 22, 1893, Serial No. 478,461.

An important feature of my invention consists in arranging the fire-box entirely in front of the boiler. By this arrangement the heated products of combustion pass along the entire inner surface of the boiler,and at the same time, the most intense heat, viz: that of the incandescent fuel, is caused to act' upon the depending water-bridge, which, at the same time, forces all of the heated and completely consumed or oxidized gases through the narrow passage-way between its lower end and the bottom grate and thence upwardly so as to act against the side opposite to the firebox, whereuponit passes through `the boiler liuc. By this arrangement, it will be noted the greatest possible amount of caloric generated by the combustion is absorbed by the water in the boiler and a great economy of fuel is attained, as will be readily understood.

In order to effect a constant and perfect circulation of the water in the boiler, my invention, in its preferred femm-furthermore, con- Vsistsin causing the bridge to communicate with the boiler, D, by means of suitable connecting devices between the boiler, D, and the water-back or bridge, B, shown in Figs. 1 and 2.

As shown in these gures, the` bridge, B, is

connected at the top and bottom thereof with the boiler proper, D, by the connecting pipes, d, d, d', d. As shown in Figs. I and 2, two pipes, d, d, extend laterally from the bottom of the water-bridge to the lower part of the boiler, D, to which they are connected or riveted in any suitable manner, and two pipes, Y

d', di', similarly connect the sides of the upper portion of the water-bridge with the upper part of the boiler, D. From the pipes, d', two bent water-delivering pipes, d?, extend upwardly above the level of the water in the boiler, where they deliver the` boiling .water and permit the dry steam to be disengaged.

I find that the best way for carrying out this lation of water rushingthrough the bridge in connection with the main body of water in the boiler. This arises from water in the bridge always being in immediate contact with the incandescent fuel and freely and quickly absorbing every particle of heat, thereby creating a constant ebullition and continuous currents of water to and from the boiler, which, on rushing away from the inverted bridge, are as quickly replaced, the action thus set up, tending to prevent incrustation or the deposit of scale on the plates and even to clear off old scale or incrustration.

It is impossible for the plates to become overheated, so long as there is a strong rush of water over them, while the constant impact of fresh particles of water on the plates instantly absorbs and carries away the heat. Another result is that steam is more freely formed than under old systems, because it can readily disen gage itself from the Water, and the more promptly the heat of combustion can be taken up by the water in the boiler, the more complete and rapid is the evaporation and production of steam and the greater the economy of fuel. The fact that heat is more rapidly transmitted by convection, or where strong circulation exists, is well-known, and therefore the means provided by this invention for rapidly absorbing and carrying away this heat creates a large `economy in fuel. t t

For feeding the fuel into the fire-box, I pro- IOC vide a hopper, H, arranged over the same and having journaled in its-bottom, two spirallyfluted feed-rollers, h, h, Figs. 1 and 4, placed overthe top of the fire-box and revolved by mechanical or other power. :By this arrange ment, `I am enabled to distribute the fuel from the box or hopper, H, onto the top of the t fire in a finely distributed showerand the quantity of fuel fed can be `accurately adjusted to the volume of air supplied., This arrangement for steam boilers may either be constructed as just described, that is in the shape of a separate attachment, or it may be incorporated and built up with and` form part ofthe boiler, as shown in Fig. 5, which represents a boiler and furnace in `all other` respects substantiallyidentical with the form shown in Fig. .1, except that-a lining of firebrick is applied at the. point, L, where the boiler is subjected to the most intense heat.

In some cases where plenty of room exists it is possible to introduce myiire-boxsystem inside of the flue of a boilerwhere the said fire-box is introduced in advance of. a horizontal fire-bed, A', for preliminarily burning IIO IZO

the fuel before it is stoked into the fire-box, A.

toproperly divert the heated current-s.` :This 1 modification also preferably comprises A.a guard plate, a', extendingupwardly and rearwardly from the top'of the front wall of the fire-box, A. This guard plate prevents the accidental introduction of green fuel from the horizontal fire-bed into the fire-box proper.

With special reference to the fire-boxes and furnaces of railroad locomotives, tramway traction and all similar engines, the inverted water-bridge or partition, B, is also made hollow and provided with suitable conections to the main body of the boiler, similar to the connecting pipes, d, d', in Figs. 1 and 2.

Vhere the fire-box is not required to generate steam, the inverted bridge between the tire-box and the combustion chamber or flue may be entirely of fire-bricks or silica bricks or of bricks specially invented by me for this purpose, which are prepared to withstand a fierce heat, or, where ordinary re bricksare employed, they may be coated with the same material from which my special fire-bricks are made. In cases where hot water is required for manufacturing and other purposes, I further economize the heat produced from the fuel and also protect the bridge by arranging behind the said fire-brick bridge,-a small boiler or other suitable apparatus; or I may employ a boiler or water-bridge instead of the fire-brick bridge. Such an arrangement is shown in Figs. 7, 8, and 9. The forms shown in these figures differ from those already described only in having the bridge, B, made partly, or entirely, of fire-brick and that the openings in the front wall of the fire box are in the shape of upright slots which may be formed by grate-bars, E4, which may be constructed and arranged as shown in Figs. 10 and 11. When made in this form, that is, as loose movable bars, there is at each end of the bars, a small pintle or journal, e2, fitted to and working in a cross bar, E3, Figs. 7 and 11, fitted at top and bottom of the fire-box. Each of these vertical bars is provided at the top with an arm, e3, Fig. l1, projecting at right angles therefrom and having on each arm a small spindle, e4, Fig. 11. These spindles, e4, are fitted to a connecting rod, E5, Fig. 11, capable of being moved to and fro by means of a knob or handle conveniently applied thereto to permit the same to be worked by hand, so as to regulate the admission of air between the bars to the fuel in the firebox or for entirely closing up the fire, as may be required, thus enabling the requisite volume of air for the perfect combustion of the fuel, to be regulated according to the quantity of fuel supplied to the tire.

In Fig. 9, the upright bars, E4, are represented as fixed (as a casting in one piece).

In this case, I provide a door, M, 'to cover the front of same, which door is provided with any suitable register, M', so that on firing up for the night and closing the register, there is no danger of falling cinders or shooting coals or sparks.

In the case of domestic and other similar tires, the fuel may be readily fed by hand as in the devices represented in Figs. 7, 8, and

9, but in other fires, where more economical and convenient, the fuel is fed by means of the spirally fluted rollers from a hopper placed overhead, as already described and shown in position in the chimney-place and the flue securely connected with the chimney.- All of these features result in the complete combustion of the fuel and a perfectly smokeless fire, such as has been attained by no system heretofore employed. It should be understood that construction is inv all cases such that no air is admitted to the fuel from under the bottom grate and where the pan, G, is employed for receiving the ashes and the water supply the same closes tightly against the furnace so as to admit no air.

While I have shown and described an ar rangement of a furnace involving some of the principles set forth,but combining therewith other features, such as a horizontal, supplemental grate, and a guard-plate, as represented in Fig. 6, I do not claim the same herein, inasmuch as it forms part of, and is claimed in, another application, filed by me on May 31, 1893, and having the Serial No. 476,050.

I hereby disclaim the constructions set forth in the United States patents to Savage, No. 221,445, dated September 6, 1858, Rand, No. 138,694, dated May G', 1873, and Bielenberg, No. 436,283, dated September 9, 1890. The patents to Rand and Bielenberg, it is true, show a fire-back extending to within a short distance of the grate, but they do not disclose a series of air-openings extending over the entire front wall of the fire-box. The patent to Savage, on the other hand, though showing the series of air-openings in the front wall, does not show a fire-back extending near enough to the bottom grate to retain all the fuel in the tire-box. My invention is confined to the combination of both of the features, separately shown in the above patents, and it is due to this combinationl that my invention results in the perfect combustion of the fuel, as set forth in' the specification.

What I claim, and desire to secure by Let'- ters Patent, ism

1. In furnaces for heating boilers and for IOO IIO

other purposes,a fire-box downwardly liaring other purposes, a fire-box comprising a bot` tom grate and a continuous unbroken bridge extending down to near the bottom grate, so as to retain all the fuel in the {ire-box and prevent its passage beyond the bridge, and a front wall having openings along its entire extent, the fire-box being closed at its top, substantially as set forth. t

3. In furnaces for heating boilers and for other purposes, a nre-box having lateral airopenlngs, in combination with a pilot-plate arranged within the fire-box, near one of the sides of the same, the top of the pilot-plate being substantially flush with the uppermost a1r-opening, substantially as set forth.

4. In furnaces for heating boilers and for other purposes, a lire-box having lateral airopenings, in combination with a pilot-plate arranged within the fire-box, near one of its sides, and beginning at a point below the top of the lire-box and extending downward a part of the depth of the nre-box, substantially as set forth.4

5. The combination, with a steam-boiler, of a water-back, a water pipe or pipes connecting the lower part of the water-back with the boiler, and a water pipe or pipes connecting a furnace, and a water-back extending down i to form one side of the furnace, a pipe or pipes connecting the lower partof thewaterback with the boiler, and a pipe or pipes connecting the upper part of the water-baci; with the boiler, and provided with a return-bend extending above the water level of the b oiler, substantially as set forth.

7. The combination, 4with a steam-boiler, of a furnace, a water -back extending `downwardly to form one side of the tire box of the furnace, a Water pipe or pipes connecting the lower portion of the water-back with the boiler, and a pipe or pipes connecting the upper part of the water-back with the boiler, and extending into the interior of the boiler above the Water-level, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

J. KNAPTON THOMPSON. Witnesses:

DAVID E. MOORE, CHAS. SHEPARD. 

